scholarly journals Evaluation of crop water demand for sustainable crop production using geospatial tools in a canal command of West Bengal

2021 ◽  
Vol 21 (4) ◽  
pp. 427-433
Author(s):  
Laishram Kanta Singh ◽  
Madan K. Jha ◽  
V.M. Chowdary ◽  
Srikanta Sannigrahi

The agricultural sector is the primary consumer of water resources around the world, and the need for additional food production for growing population further exerts more pressure on water resources. In this study, crop water demand was assessed spatially and temporally for a case study area, Damodar Canal Command (DCC) using geospatial techniques. Crop evapotranspiration was estimated for all the crop seasons using reference evapotranspiration and Fraction of Vegetation cover (FV) that was used as a surrogate for crop coefficient. The reference evapotranspiration (ET ) was calculated using the FAO o Penman-Monteith method. FV was computed based on Normalized Difference Vegetation Index (NDVI) derived from MODIS satellite imagery and its value ranges from 0 to 1. The maximum and minimum reference evapotranspiration values were estimated as 8.44 and 1.88 mmday-1 in May and September, respectively during the normal year 2004. The average monthly crop water demand was maximum in May i.e. 8.08 mmday-1. Among all crop seasons, Boro season has the maximum crop water demand followed by Aus and Aman seasons with maximum ET as 496, 438 and 328 mm, respectively. Total annual crop c water demand for normal year, 2004 was estimated at 1237 mmyr-1 in the study area. Spatially and temporally distributed crop water demand estimates help the irrigation planners to devise the strategies for effective irrigation management.

2019 ◽  
Vol 11 (3) ◽  
pp. 67 ◽  
Author(s):  
Sara Fenech ◽  
Jerry Knox ◽  
Malcolm Borg ◽  
Christian Camilleri ◽  
Alex Rizzo

Estimating evapotranspiration is crucial for better management of catchment water resources. In this study, the FAO CropWat model was used to estimate reference evapotranspiration (ETo), crop evapotranspiration (ETc), and total gross water requirements for three economically important agricultural crops grown in Malta: potatoes, wheat, and vineyards for three years representative of a typically wet (2003), average (2009), and dry (2013) year. In addition, changes in ETc due to changes in land use were estimated for 2009 and 2013 relative to a 2003 baseline. Across all three years and crops, the average ETo rates were estimated to range between 3.7 mm day -1 (2003) and 4.0 mm day-1 (2013) while average ETc rates were estimated to range between 1.6 mm day-1 and 5.3 mm day-1, respectively. For all three years, the highest total gross water requirement was estimated for wheat, reaching a maximum of 1450 mm in 2013. The results suggest that changes in land use between 2003 and 2013 were the main driver for changes in crop water demand. Differences in water demand compared to 2003 were estimated to range between -38% and 60%. This could have a substantial impact on the future sustainability of Malta’s increasingly constrained water resources.


2021 ◽  
Author(s):  
Smaranika Mahapatra ◽  
Madan Kumar Jha

<p>Agricultural sector, being the largest consumer of water is greatly affected by climatic variability and disasters. Most parts of the world already face an enormous challenge in meeting competitive and conflicting multi-sector water demands. Climate change has further exacerbated this challenge by putting the sustainability of current cropping patterns and irrigation practices in question. For ensuring climate-resilient food production, it is crucial to examine the patterns of the projected climate and potential impacts on the agricultural sector at a basin scale. Hence, this study was carried out for an already water-scarce basin, Rushikulya River basin (RRB), located in the coastal region of eastern India. The bias-corrected NorESM2-MM general circulation model of Coupled Model Intercomparison Project-6 (CMIP6) was used in this study under four shared socioeconomic pathway (SSPs) scenarios, namely SSP126, SSP245, SSP370 and SSP585. The projected climatic parameters and crop water demands of the basin were analyzed assuming existing cropping pattern in the future. Analysis of the results reveals a significant and rapid increase in the temperature at a rate of 0.02-0.5ºC/year during 2026-2100 under all SSPs except SSP126, whereas the rainfall is expected to increase slightly during 2026-2100 as compared to the baseline period (1990-2016), especially in the far future (2076-2100) under all the SSPs. In contrast, monsoon rainfall is predicted to decrease under SSP245 and SSP370, while a slight increase in the monsoon rainfall is evident under SSP126 and SSP585. Although the rainy days will decrease slightly in the future 25-year time window, the number of heavy rainfall events is predicted to increase by two to three times. Also, retrospective analysis of rainfall and evapotranspiration suggested an existence of rainfall deficit (rainfall-evapotranspiration) in the basin throughout the year, except during July to September. The rainfall deficit in the basin during 2026-2100 is found to remain more or less same in the non-monsoon season, except for the month of October under SSP245, SSP370 and SSP585 scenarios where deficit increases by two folds. Rainfall is expected to be in surplus by 4 to 5 times higher under all SSPs except for SSP245. As to the evapotranspiration, an insignificant increasing trend is observed under future climatic condition with only 2 to 4% rise in the crop water demand compared to the baseline period. As the basin is already water stressed during most months in a year under baseline and future climatic conditions, continuing the current practice of monsoon paddy dominant cultivation in the basin will further aggravate this situation. The results of this study will be helpful in formulating sustainable irrigation plans and adaptation measures to address climate-induced water stress in the basin.</p><p><strong>Keywords:</strong> Climate change; CMIP6; SSP; Monsoon rainfall; Temperature; Crop water demand.</p>


Agronomy ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 108 ◽  
Author(s):  
Jason Kelley ◽  
Eric Pardyjak

Irrigation efficiency is facilitated by matching irrigation rates to crop water demand based on estimates of actual evapotranspiration (ET). In production settings, monitoring of water demand is typically accomplished by measuring reference ET rather than actual ET, which is then adjusted approximately using simplified crop coefficients based on calendars of crop maturation. Methods to determine actual ET are usually limited to use in research experiments for reasons of cost, labor and requisite user skill. To pair monitoring and research methods, we co-located eddy covariance sensors with on-farm weather stations over two different irrigated crops (vegetable beans and hazelnuts). Neural networks were used to train a neural network and utilize on-farm weather sensors to report actual ET as measured by the eddy covariance method. This approach was able to robustly estimate ET from as few as four sensor parameters (temperature, solar radiation, humidity and wind speed) with training time as brief as one week. An important limitation found with this machine learning method is that the trained network is only valid under environmental and crop conditions similar to the training period. The small number of required sensors and short training times demonstrate that this approach can estimate site-specific and crop specific ET. With additional field validation, this approach may offer a new method to monitor actual crop water demand for irrigation management.


2020 ◽  
Author(s):  
Fatima Ezzahra El Ghandour ◽  
Adnane Habib ◽  
Youssef Houali ◽  
Yassine Labbassi ◽  
Lorenzo Iannini ◽  
...  

<p>Investigations carried out under the MOSESH2020 project in the Doukkala irrigation scheme (western Morocco) allowed the generation of several data products during the agricultural seasons 2016-2017 and 2017-2018: Seasonal probabilistic weather forecast, Early-season and In-season crop mapping, Monitoring of crop water demand and Short-term forecasts of irrigation water requirements.</p><p>This study was focused on the assessment of the adequacy of the water applied to meet the crop water demand in the two irrigation seasons 2016-2017 and 2017-2018.</p><p>Monitoring of Crop Water Demand (CWD) was based on the estimation of the maximum crop evapotranspiration, obtained from remote sensing data of the monitored area. Such output is updated frequently (e.g. every week) during the irrigation season and compared to the weekly surface irrigation water volumes allocated. Although the assessment of adequacy of allocations against the crop water demand (CWD) showed that the latter was much larger with 10-15% than allocated surface water for the entire area, with this difference being small at the beginning of the growing season.</p><p>The use of MOSES products during the irrigation management operations would help the water management authority to save water, especially during the winter season, leaving additional water available to meet requirements in spring and summer.</p>


Irriga ◽  
2002 ◽  
Vol 7 (3) ◽  
pp. 185-190
Author(s):  
Ana Alexandrina Gama da Silva ◽  
Antonio Evaldo Klar

DEMANDA HÍDRICA DO MARACUJAZEIRO AMARELO (Passiflora edulis Sims f. flavicarpa Deg.)   Ana Alexandrina Gama da SilvaEmbrapa Tabuleiros Costeiros, CP 44, CEP 49025-040, Aracaju, SE. E-mail: [email protected] Evaldo KlarDepartamento de Engenharia Rural, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, CP 237, CEP 18603-970, Botucatu, SP. E-mail: [email protected] Científico do CNPq   1 RESUMO  Determinou-se à demanda hídrica e o coeficiente de cultivo (Kc) do maracujá amarelo (Passiflora edulis Sims f. flavicarpa Deg.), seleção Sul-Brasil, cultivado sob irrigação localizada, no município de Botucatu-SP (22o 51’ S,  48o 26’ W). A evapotranspiração máxima da cultura (ETc) e a evapotranspiração de referência (ETo) foram medidas em lisímetros de nível de lençol freático constante, durante o período de 29 de setembro de 2000 a 20 de julho de 2001. Os valores da ETc e ETo foram de 954,98 mm e  1.069,21 mm, respectivamente, durante todo o período medido. Os valores de Kc variaram de 0,42 a 1,12, com os valores máximos registrados entre 150 e 210 dias após o transplantio das mudas no campo (DAT), período correspondente aos estádios fenológicos de florescimento e formação dos frutos.  UNITERMOS: Passiflora edulis, evapotranspiração, coeficiente de cultivo (Kc).   SILVA, A.A.G. da, KLAR, A.E.  YELLOW PASSION FRUIT (Passiflora edulis Sims f. flavicarpa Deg.) CROP: WATER DEMAND.   2 ABSTRACT  Crop water demand and crop water coefficient (Kc = ETc/ETo) of yellow passion fruit were evaluated in constant level lysimeters under drip irrigation from September 21, 2000 to July 31, 2001 in Botucatu-SP. The maximum crop water demand (ETc) and the Reference Evapotranspiration (ETo), measured by lysimeters, were 954.98 mm and 1,069.21 mm, respectively, during all period measured. The values of Kc varied from 0.42 to 1.12  with maximum values registered from 150 to 210 days following transplanting during flowering and fruit formation  phases.  KEYWORDS: Passiflora edulis, evapotranspiration, crop coefficient (Kc). 


2018 ◽  
Author(s):  
Xiao-Bo Luan ◽  
Ya-Li Yin ◽  
Pu-Te Wu ◽  
Shi-Kun Sun ◽  
Yu-Bao Wang ◽  
...  

Abstract. Fresh water is consumed during agricultural production. With the shortage of water resources, assessing the water use efficiency is crucial to effectively managing agricultural water resources. The water footprint is a new index for water use evaluation, and it can reflect the quantity and types of water usage during crop growth. This study aims to establish a method for calculating the region-scale water footprint of crop production based on hydrological processes. This method analyzes the water-use process during the growth of crops, which includes irrigation, precipitation, underground water, evapotranspiration, and drainage, and it ensures a more credible evaluation of water use. As illustrated by the case of the Hetao irrigation district (HID), China, the water footprints of wheat, corn and sunflower were calculated using this method. The results show that canal water loss and evapotranspiration were responsible for most of the water consumption and accounted for 47.9 % and 41.8 % of the total consumption, respectively. The total water footprints of wheat, sunflower and corn were 1380–2888 m3/t, 942–1774 m3/t, and 2095–4855 m3/t, respectively, and the blue footprint accounts for more than 86 %. The spatial distribution pattern of the green, blue and total water footprint for the three crops demonstrated that higher values occurred in the eastern part of the HID, which had more precipitation and was further from the irrigating gate. This study offers a vital reference for improving the method used to calculate the crop water footprint.


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